[unreadable] We have devised a technique that will greatly simplify and make cost effective the fabrication of dense silicone membrane hollow fibers (SMHF) for use in blood gas exchange applications including long-term extracorporeal life support, implantable artificial lung, and other cardiorespiratory procedures. The SMHF can be used to make non-porous, high performing, and economically attractive compact oxygenators, analogous to microporous membrane hollow fiber (MMHF) devices. Current devices using MMHF are prevalent because of enhanced gas exchange due to the convective mixing induced by blood flowing over thousands of tiny hollow fibers. This property allows for designing highly efficient gas exchange devices in relatively compact volumes. Yet MMHF suffer from fowling, and plasma leakage when they are used for extended periods of time, and from gas embolization when the gas side pressure exceeds the blood side pressure. Nonetheless there is currently no analogous non-microporous hollow fiber oxygenators. The present SMHF incorporates the compactness and effectiveness of MMHFs plus the ability to withstand plasma leakage and gas embolization. In Phase 1 we demonstrated that the SMHF can be fabricated continuously and reliably using our proprietary process, and that test oxygenating modules using our SMHF perform comparably to the MMHF counterparts. In Phase 2 we propose to further develop and scale-up the fabrication technique to evaluate the gas exchange, hemodynamic performance, and resistance to plasma breakthrough of the SMHF in adult size oxygenators. These studies will be performed on the bench as well as in-vivo. [unreadable] [unreadable]